Zinc Catalysts for On-Demand Hydrogen Generation and Carbon Dioxide Functionalization

[Tris(2-pyridylthio)methyl]zinc hydride, [kappa(3)-Tptm]ZnH, is a multifunctional catalyst that is capable of achieving (i) rapid release of hydrogen by protolytic cleavage of silanes with either water or methanol and (ii) hydrosilylation of aldehydes, ketones, and carbon dioxide. For example, [kappa(3)-Tptm]ZnH catalyzes the release of 3 equivalents of H-2 by methanolysis of phenylsilane, with a turnover number of 10(5) and a turnover frequency surpassing 10(6) h(-1) for the first 2 equivalents. Furthermore, [kappa(3)-Tptm]ZnH also catalyzes the formation of triethoxysilyl formate by hydrosilylation of carbon dioxide with triethoxysilane. Triethoxysilyl formate may be converted into ethyl formate and N,N-dimethylformamide, thereby providing a means for utilizing carbon dioxide as a C-1 feedstock for the synthesis of useful chemicals.